全文获取类型
收费全文 | 1002篇 |
免费 | 99篇 |
国内免费 | 30篇 |
专业分类
化学 | 170篇 |
力学 | 63篇 |
综合类 | 17篇 |
数学 | 38篇 |
物理学 | 843篇 |
出版年
2024年 | 1篇 |
2023年 | 7篇 |
2022年 | 15篇 |
2021年 | 23篇 |
2020年 | 23篇 |
2019年 | 17篇 |
2018年 | 13篇 |
2017年 | 46篇 |
2016年 | 68篇 |
2015年 | 60篇 |
2014年 | 72篇 |
2013年 | 43篇 |
2012年 | 72篇 |
2011年 | 56篇 |
2010年 | 39篇 |
2009年 | 49篇 |
2008年 | 63篇 |
2007年 | 47篇 |
2006年 | 50篇 |
2005年 | 53篇 |
2004年 | 52篇 |
2003年 | 46篇 |
2002年 | 31篇 |
2001年 | 24篇 |
2000年 | 30篇 |
1999年 | 16篇 |
1998年 | 23篇 |
1997年 | 14篇 |
1996年 | 11篇 |
1995年 | 9篇 |
1994年 | 12篇 |
1993年 | 9篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1131条查询结果,搜索用时 46 毫秒
101.
102.
103.
Lszl Domjn Lszl Kocsnyi Pter Richter va Jeszenszky 《Optics and Lasers in Engineering》2003,40(3):201-223
Achieving good signal-to-noise ratio (SNR) against solar illumination is a basic requirement for the light source of active vision sensors in outdoor applications. The article examines the high power stripe-lighting setup, constructed with a cylindrical lens and a rectangular emitting source placed at the focal line of the lens. This source type is capable of illuminating a very high total power because of the large surface size of the emitter; thus it is advantageous for outdoor applications. A detailed radiometric analysis of this setup is presented resulting in an integral for the calculation of the spatial irradiance distribution within the stripe. The achievable SNRs against solar illumination are calculated by applying the radiometric integral for different rectangular emitters built of LED arrays, laser diode arrays and incandescent sources. The article proposes stripe illuminators applying all the analyzed emitter types that are suitable for operation in direct sunshine. 相似文献
104.
采用GaAlAs单量子阱半导体激光器和LD泵浦的Nd:YVO4-KTP倍频激光器等研制了国内首台可从光导纤维输出5种波长的半导体激光生物组织辐照仪,该仪器已在激光生物医学领域投入应用. 相似文献
105.
A stereo disparity-based range finding technique was developed for measuring three-dimensional coordinates of object points. It used an image-matching algorithm which functionally consisted of scene reduction, epipolar line selection, and features matching. Experiments implementing this technique were performed on an industrial vision system. An error analysis indicated that image resolution was the major source of measurement inaccuracy. 相似文献
106.
The key modules in a typical reverse engineering system consist of the acquisition, registration, and the integration of range images of three-dimensional objects with complex geometry. We first present a self-made optical digitizer that is employed for quickly acquiring range data from multiple views, then introduce a visualized registration procedure that can provide a reliable estimate for the fine registration of multiple range images in a unified coordinate system. Experiment results are given to show the effectiveness of this approach in 3-D imaging and multiple range image registration for the applications of reverse engineering. 相似文献
107.
介绍三代微光和超二代微光夜视技术的发展概况:阐明了它们各自的原理、技术特点和关键课题;着重指出了两者间的异同和相互联系。 相似文献
108.
109.
110.
In many decision making systems involving multiple sources, the decisions made may be considered as the result of a rule-based system in which the decision rules are usually enumerated by experts or generated by a learning process. In this paper, we discuss the various issues involved in the generation of fuzzy rules automatically from training data for high-level computer vision. Features are treated as linguistic variables that appear in the antecedent clauses of the rules. We present methods to generate the corresponding linguistic labels (values) and their membership functions. Rules are generated by constructing a minimal approximate fuzzy aggregation network and then training the network using gradient descent methods. Several examples are given. 相似文献